package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.constant.MessageConstant;
import com.hmdp.constant.RedisConstant;
import com.hmdp.constant.SystemConstants;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IUserService;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {

    @Resource
    private IUserService userService;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private FollowServiceImpl followService;

    @Override
    public Result queryHotBlog(Integer current) {
        // 根据用户查询
        Page<Blog> page = query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
        records.forEach(blog->{
            this.queryBlogUser(blog);
            //3.查询blog是否被点赞
            this.isBlogLiked(blog);
        });
        return Result.ok(records);
    }


    @Override
    public Result queryBlogById(Long id) {
        //1.查询blog
        Blog blog = getById(id);
        if(blog ==null){
            return Result.fail(MessageConstant.BLOG_NOT_EXIST);
        }
        //2.查询blog相关用户
        queryBlogUser(blog);
        //3.查询blog是否被点赞
        isBlogLiked(blog);
        return Result.ok(blog);
    }

    private void isBlogLiked(Blog blog) {
        //1.获取登录用户
        UserDTO user = UserHolder.getUser();
        if(user==null){
            //未登录
            return;
        }
        Long userId = user.getId();
        //2.判断是否点赞过
        String key = "blog:liked:"+blog.getId();
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        blog.setIsLike(score!=null);
    }

    @Override
    public Result likeBlog(Long id) {
        //1.获取登录用户
        Long userId = UserHolder.getUser().getId();
        //2.判断是否点赞过
        String key = RedisConstant.BLOG_LIKED_KEY +id;
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        //3.如果没有点赞 可以点赞
        if(score==null){
            //3.1数据库点赞数+1
            boolean isSuccess = update().setSql("liked=liked+1").eq("id", id).update();
            //3.2保存用户到redis的set集合
            if(isSuccess){
                stringRedisTemplate.opsForZSet().add(key,userId.toString(),System.currentTimeMillis());
            }
        }else{
            //4.已点赞 取消点赞
            //4.1数据库点赞数量-1
            boolean isSuccess = update().setSql("liked=liked-1").eq("id", id).update();
            //4.2把用户从Redis的set集合中移除
            if(isSuccess){
                stringRedisTemplate.opsForZSet().remove(key,userId.toString());
            }
        }
        return Result.ok();
    }

    @Override
    public Result queryBlogLikes(Long id) {
        //1.查询top5的点赞用户
        String key = RedisConstant.BLOG_LIKED_KEY+id;
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        if(top5==null||top5.isEmpty()){
            return Result.ok(Collections.emptyList());
        }
        //2.解析出用户id
        List<Long> ids = top5.stream().map(Long::valueOf).collect(Collectors.toList());
        String idStr = StrUtil.join(",", ids);
        // 根据id降序排序 select * from tb_user where id in(1,5) order by field(id, 1, 5)
        List<UserDTO> userDTOList = userService.list(new LambdaQueryWrapper<User>()
                        .in(User::getId, ids)
                        .last("order by field (id," + idStr + ")"))
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());
        //4.返回
        return Result.ok(userDTOList);
    }

    @Override
    public Result saveBlog(Blog blog) {
        //1.获取登录用户
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        //2.保存探店笔记
        boolean isSuccess = save(blog);
        if(!isSuccess){
            return Result.fail(MessageConstant.CREATE_BLOG_FAIL);
        }
        //3.查询笔记作者的所有粉丝 select * from tb_follow where follow_user_id = ?
        List<Follow> follows = followService.query().eq("follow_user_id", user.getId()).list();
        //4.推送比较id给所有粉丝
        for(Follow follow:follows){
            //4.1获取粉丝id
            Long userId = follow.getUserId();
            //4.2 推送
            String key = RedisConstant.FEED+userId;
            stringRedisTemplate.opsForZSet().add(key,blog.getId().toString(),System.currentTimeMillis());
        }
        //5.返回id
        return Result.ok(blog.getId());
    }

    /**
     * 关注推送页面的笔记分页
     *
     * @param max
     * @param offset
     * @return
     */
    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        // 1、查询收件箱
        Long userId = UserHolder.getUser().getId();
        String key = RedisConstant.FEED + userId;
        // ZREVRANGEBYSCORE key Max Min LIMIT offset count
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 2);
        // 2、判断收件箱中是否有数据
        if (typedTuples == null || typedTuples.isEmpty()) {
            return Result.ok();
        }

        // 3、收件箱中有数据，则解析数据: blogId、minTime（时间戳）、offset
        List<Long> ids = new ArrayList<>(typedTuples.size());
        long minTime = 0; // 记录当前最小值
        int os = 1; // 偏移量offset，用来计数
        for (ZSetOperations.TypedTuple<String> tuple : typedTuples) { // 5 4 4 2 2
            // 获取id
            ids.add(Long.valueOf(tuple.getValue()));
            // 获取分数（时间戳）
            long time = tuple.getScore().longValue();
            if (time == minTime) {
                // 当前时间等于最小时间，偏移量+1
                os++;
            } else {
                // 当前时间不等于最小时间，重置
                minTime = time;
                os = 1;
            }
        }

        // 4、根据id查询blog（使用in查询的数据是默认按照id升序排序的，这里需要使用我们自己指定的顺序排序）
        String idStr = StrUtil.join(",", ids);
        List<Blog> blogs = query().in("id",ids).last("ORDER BY field (id," + idStr + ")").list();
        // 设置blog相关的用户数据，是否被点赞等属性值
        for (Blog blog : blogs) {
            // 查询blog有关的用户
            queryBlogUser(blog);
            // 查询blog是否被点赞
            isBlogLiked(blog);
        }

        // 5、封装并返回
        ScrollResult scrollResult = new ScrollResult();
        scrollResult.setList(blogs);
        scrollResult.setOffset(os);
        scrollResult.setMinTime(minTime);
        return Result.ok(scrollResult);
    }


    private void queryBlogUser(Blog blog ){
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }
}
